(Scanned from Polmar and Carpenter's "Submarines
of The Imperial Japanese Navy")

This was the most numerous class of Japanese submarines. These boats were
fast, long-ranged, and carried a seaplane, which could be launched on a forward
catapult. However, I-17 carried the catapult aft, and her hangar opened
aft as well. During the war, the aircraft facilities were removed from
some boats in order to mount a second 14cm gun. In 1944, I-36 and I-37
were modified to carry four Kaiten, and I-36 was later modified again to carry
six Kaiten.

They were used extensively and had their share of
successes. On 31 August 1942, I-26 damaged aircraft carrier USS Saratoga with one torpedo hit (out of six launched), removing her from
the Guadalcanal campaign at a critical time. Two weeks later, on 15 September, I-19 achieved an
incredible success when she fired six torpedoes at aircraft carrier USS
Wasp. Two of these hit the carrier forward and ignited gasoline storage, dooming the ship. The remaining four torpedoes
of this salvo went several thousand yards further and encountered a second
American carrier task force, damaging battleship USS North Carolina enough to require two months to
repair, and sinking destroyer USS O'Brien. This was among the most
damaging torpedo salvoes in history. On 13 October, it was again the turn of I-26
as she finished off USS Juneau, one of several damaged
and unescorted American cruisers which survived the First Naval Battle of
Guadalcanal the evening before. The loss of life on USS Juneau was extreme,
including the five Sullivan brothers. Bagnasco credits all of the Type B
boats (B1, B2, and B3 combined) with sinking 56 merchant ships of 372,730 GRT.

Of
these 20 boats, 95% were lost during the war, and only I-36 survived. I-15
was lost off San Cristobol on 2 November 1942 to destroyer USS McCalla.
I-17 was sunk by New Zealand trawler Tui and 2 US Navy aircraft off Noumea on 19
August 1943. I-19 was probably lost to attack by US Navy aircraft on 18
October 1943. I-21 was lost to aircraft from escort carrier USS Chenango
on 29 November 1943. I-23 was an operational loss in February of
1942. Destroyer USS Patterson sank I-25 off the New Hebrides on 3
September 1943. I-26 survived until October 1944, when she became an
operational loss off Leyte. I-27 was sunk by HMS Paladin and HMS Petard
off Addu Atoll on 12 February 1944. I-28 was torpedoed by submarine USS
Tautog south of Truk on 17 May 1944, and I-29 received similar treatment from
USS Sawfish in Balintang Channel on 26 July, 1944. A mine claimed I-30 off
Singapore on 13 October 1942. I-31 was lost to destroyers USS Edwards and
USS Farragut off Kiska 12 May 1943. I-32 was sunk by destroyer escort USS
Manlove and PC 1135 south of Wotje 24 March 1944. I-33 was an operational
loss during sea trials in the Inland Sea 13 June 1944. I-34 was sunk by
submarine HMS Taurus off Penang 13 November 1943. Destroyers USS Meade and
USS Frazier sank I-35 off Tarawa 23 November 1943. I-36 was the sole
survivor among this class, and was scuttled off Goto Island 1 April 1946.
Destroyer escorts USS Conklin and USS McCoy Reynolds sank I-37 off Leyte 19
November 1944. I-38 was lost to destroyer USS Nicholas south of Yap 12
November 1944, while destroyer USS Boyd eliminated I-39 in the Gilberts 26
November 1943.